There exists a requirement for screening of cargo items for detection of illicit materials and devices. One class of screening device comprises a truck platform upon which is mounted a high energy X-ray linear accelerator and a series of X-ray detectors. The X-ray detectors are advantageously mounted on a hydraulically operated boom so that the system can be deployed to form a scanning system.
When an object is to be inspected, the entire truck is driven past the stationary object such that the object passes through the X-ray beam between the X-ray source and the X-ray detector array. X-ray projection data is built up line-by-line to form a two-dimensional image.
A mobile truck screening system typically comprises a standard truck chassis with integral drivers cab. Built onto the flat bed at the back of the truck is an inspectors cab and the X-ray imaging device which typically comprises a hydraulically operated boom and X-ray linear accelerator. There is typically an operational exclusion zone around the truck during the scanning process to reduce the X-ray exposure to personnel in the vicinity of the screening area to an acceptable level. A typical exclusion zone dimension is around 30 m×30 m.
The inspectors pod is typically formed from dense materials such as steel and lead so that radiation which is scattered from the object under inspection is attenuated to result in a dose to the inspector that is of an acceptable level. The inspector is usually involved in reviewing image data to verify the presence or otherwise of illicit materials or devices in the cargo load. The inspector may also be involved in operation of the truck system, for example in scanning manifest information or monitoring of the technology that is used on the truck itself.